* state(pack_project): New function.

* tests: New tests.

* tests
  Stages `build' and `test' reinstated and working.
* Dockerfile
  Tweaks to make testing using `test' command operational.

Also, adapt code affected by this elsewhere.

* metfrag(summarise_metfrag_results): Update.

* state(new_runtime_state, metfrag_conf): Update.

* metfrag(metrag_run): Update.

* envopts: New option `java_bin'.

* resources: New parameter METFRAG_DB_SEARCH_RELDEV.

* state (new_runtime_state, metfrag_conf, get_metfrag_targets,
write_metfrag_config, metfrag_run_many): Update. Running many configs
now works.

* tests: Update.

* state (base_conf): Update. Decorates the return object with class
`state'. New class `state'.
(get_metfrag_targets, metfrag_on_state): New functions.
(write_metfrag_config): Update. Add checks for ion_mz and adduct not
being more, or less than one. Also, make filenames nicer and fix the
spectral separator.

(metfrag_run_many, metfrag_run_many_w_futures): New functions to run
metfrag.

tests: New tests and snapshots.

* base.R (write_keyval_file): New function.

* resources.R (METFRAG_ADDUCT_SWITCHES): Fix a typo.

* state.R (new_runtime_state): Update results with the new field
`subpaths'. Also, opted for relative vs absolute paths, because the
latter do not play well with tests in (stochastic) temporary
directories.

(base_conf): Update result to have a class `conf' signature.

(metfrag_conf): Update with new parameters.

(new_conf): Update with a call to `metfrag_conf'.

(write_metfrag_config): New function which writes the MetFrag config
file.

* tests/testthat/test-metfrag.R: New file with MetFrag tests.

* tests/testthat/_snaps/metfrag.md: New file .

* envopts (envopts): Update. Normalise MetFrag paths.

* resources (METFRAG_DATABASE_TYPE, METFRAG_REMOTE_DATABASE_TYPE,
METFRAG_LOCAL_DATABASE_TYPE): Updated. Rearranged for finer control.

* shiny-state (make_metfrag_panel): New function.

* shiny-ui-base (mf-database-type): New observer.
(cando_metfrag, metfrag_panel): New outputs.

* app (MetFrag): Update section header. Delete hardwired controls.
(metfrag_panel): New control which replaced the hardwired controls.

tests: Update with new functionality.

* api: Update with new error variables.

* errors: New file to define error conditions.

* state (init_state, is_metfrag_available, new_runtime_state,
new_empty_project, new_project, ^.*_conf funs): Some updated, some
new.

* test-state: Update with tests for new functionality.

* DESCRIPTION: New version and doc engine.

* NAMESPACE: Adapted.

* man: Updated.